Brightener composition for paper derived from metanilic and sulfanilic acids



* United States Patent BRIGHTENER COMPOSITION FOR PAPER DERIVED FROM METANILIC AND SULFA- NILIC ACIDS v I a Frederick G. Villaume, Martinsville, NJ., assignor to American Cyanamid Company, New York, N.Y., a

corporation of Maine No Drawing. filed Dec. ,15, 1961, Ser. No. Y 9 Claims. (Cl. 252301.2)

' This invention relates to an improved brightene'r composition; to a process for brightening paper therewith; and to the biightened paper provided. a 'Ilhe brightener composition ofthis invention it its acid form is represented by the following:

SOQH

an: R

V H scan and para-sulfophenyl radicals, i.e.,

the entire compositionbeing between about 0.33 0.66

r DASfmoiety. The symbol DAS is used herein;

to denote the following divalent stilbene radical:

soar: V "scan Thus the brightening composition of this invention can ohnlrdicalsin I the average occurrence of meta-suit p e y a composltlon mfg present mvemlon.

to 1:2, the composition iii-any event being a mixture oi at I 1east-two of the following three compounds.

' N N 1 -no'oimNrwf Tnlis-(fiTNHoiHion N N, N

IIIH

S 03H SOa Compound B 1 applied to the'paper pulp during a 0.15% level to a 5% I The invention likewiseconte degree of 3,132,106 Patented May 5, 1964.

DAS-f TNHOaHqOH Compound C V N HOCzHANH r NIhICzHsOH I NH l mplates acid andneutral salts of the foregoing sulfonic acids with inorganic bases such as alkali metal bases, e.g., sodium, potassium and ammonium hydroxides and carbonates. H'eretofore DAS 'triazine brighteners have been used to neutralize the yell-owishtinge of natural or un-- treated paper, thereby giving it :an optically bright, i.e., a'white, appearance. From a comrncrcialviewpoiut, known DAS brighteners are disadvantageous inespecially one respect, that is, they do not show their normal fullblue fluorescence when applied under acidic conditions such as are encountered conventional paper making processes. This objection applies to a degree, even to the very components which make up the brightening The P o p p; during mastication", i.e., in the beater operation, ofiten is as low as 4.2 as a result of the use of precidified pulp, i.e., one in which alumin is added before any of the other ingredients, hr the use of a white water, i.e;, recovered liquor from previous beater operations, as the beater liquor. The disadvantage is thus manifested when the brightener is added to paper pulp bet ore it is converted into sheet paper. Moreover, in some cases these brighteners actually cause additional yellowing of the }paper,the

yellowing increasing with brightener concentra- 7 l The present invention is the DAS triazine brightener composition of the present invention is a superior brightener ior'paper even when a manutacturing operation. This composition shows a definite advantage in increased pI-I stability and increased water solubility over other DAS triazine brighteners, even bver the component DAS which make up the brightener conipositioii of this invention. They may thus be "used in relatively high concentrations to treat pulp under low pH conditions without increasing yellowness in the paper pulp; Thus, for example, a-mixture containing equal parts of coinpound A and compound B,described above, is added at paper pulp having a pH of 4.3 during the beater'operation. The resultantpaper when, viewed under ultraviolet light fluoresces much more.

strongly than a sheet of papermadecfirom paper.

pulp using the same level of compound A alone, or'compound B alone. viewed in daylight, the paper made with compound A appears definitely yellow, even more yellow than ablank sheet-prepared without the brightener. The sheet made using compound B' appears just perceptibly yellow, but whiter than a blank sheets based 'on the :discovery that;

. 1 lowness.

Yellowness Fluorescence Compound A 11.0 8.2 Compound B 7.6 9.5 Brightener of this invention 6. 9 10. 8

the yelllowness of the mixed bright- It is apparent (that alone, and its ener is less than that of either component fluorescence is considerably greater.

It is an advantage of the present invention that the brightener composition thereof may be made in any of several alternative ways. Thus, for example, preformed compound A may be mechanically mixed with preformed compound B in theproper proportions, or alternatively cyanuric' chloride may be reacted with diaminostilbenedisulfonic acid, ethanolamine acids, the last two components being in a ratio of between 1:2 and 2:1. Howsoever prepared, the brightener mixture within the scope of the present invention showsthe aforementioned advantages.

It is a further advantage of the brighteners of the present invention that they are more soluble in water than'any of the single component brighteners taken individually. Thus, for example, compound B will form a 15 %'solution in 25% aqueous triethanolamine but in water alone cannot form even a 15% solution. Contrasted with this, a brightener of the present invention,

e.g., having an average of one meta-sulfophenyl radical per DAS moiety will form a 21% solution in water alone. This increased solubility is advantageous in that it allows for the use of more concentrated stock solutions.

While the brightener of the present invention can be applied in the pulp stage, it is not limited to such application. When applied to the paper in sheet form, the application step may be combined either with a finishing or sizing operation by incorporating the brightener into the finishing compositions. The amount of brightener added to the paper is not highly critical, since the usage depends on the desired degree of brightening. In preferred practice a range of 0.01% to 0.2% based on the weight of the dry paper stock is used, since good brightening isobtained economically.

Any conventional paper stock may be brightened by the practice of this invention including paper produced from ground wood pulp, sulfite pulp and other pulps or mixtures thereof. r

This invention is further illustrated by the following examples in which parts are on a weight basis. 7

Example 1 A mixture of 37 parts of 4,4-diaminostilbene-2,2'- disulfonic acid (in the form of its disodium salt) in 360 parts of water with 270 parts of acetone is cooled to about C. A solution containing 36.9 parts of cyanuric chloride in 200 parts of acetone is added rapidly. and after stirring for about 5 minutes, the mixture is neutralized with a 15% aqueous solution of sodium carbonate (gradually over a' 30-minute period). To the gelled condensation mixture is metanilic acid and 17.3 parts of sulfanilic acid. The reaction mixture is heated to 30 C. and then gradually neutralized with sodium carbonate solution (over an overnight period);

After this secondary reaction is completed at 30 C., 36 parts of monoethanolamine are added and the acetone solvent is removed by distillation below 100 "C. The mixture is then heated at the reflux temperature for about one hour to complete the final reaction. After clarification a clear aqueous solution of the brightener is obtained;

and sulfanilic and metanilic 7 resultant sheet is still clear white.

then added 17.3 parts of ,basis) as a 13.5%

The procedure of 23.1 parts of metanilic acid and 11.5 parts of sulfanilic acid are used in place of the 17.3 parts of each used therein.

Example 3 v The procedure of Example 1 is followed except that 11.5 parts of metanilic acid and 23.1 parts of sulfanilic acid are used in place of the 17.3 parts of each used therein.

Example 4 A beater mixture is prepared using 200 parts of dry bleached sulfite pulp in 4,000 ml. water (making a 5.0% consistency pulp), and 30 ml. of 10.0% alum. Then 0.14 part of the brightener composition of Example 1 is added (0.07% concentration on the dry pulp aqueous solution. The batch is stirred for one-half hour and handsheets are formed. The sheets are clear white and fluorescent without any evidence of yellow coloration. V

When the same experiment is performed using in place of the above brightner composition an equal weight (0.14 part) of a single chemical compound, namely compound A, above, a pronounced yellow coloration of the paper sheet is observed in daylight, and the sheet is unsatisfactory for use as a pure white sheet.

When the same experiment is performed using three times the quantity of brightener composition (namely 0.42 part, or 0.2% on the weight of the pulp) the 7 On the other hand, substitution of 0.42 part of compound A gives a strongly yellow-tinted sheet. Substitution of 0.42 part of compound B gives a sheet with a very slight yellow coloration in daylight.

. Example 5 A white water formulation similar to that encountered in actual manufacturing processes is prepared using 4,000 m1. tap water, 10 ml. of commercial sodium silicate solution, 5 ml. of 4.0% rosin and sufficient 10% alum solution to bring the pH to 5 .5.

V A 5.0% consistency bleached sulfite pulp composition is made up using this white water with 200 parts of dry bleached sulfite pulp and 13 parts of clay. This is stirred 10 minutes and then 70 ml. of 4.0% rosin (pH 7.6) is added. The mixture is stirred an additional 10 minutes, then 0.14 part of the brightener composition of Example 2 is added as a 13.5% solution and the mixture is stirred for another 10 minutes. After adding 68 ml. of 10.0% alum (p11. 4.0), the mixture is stirred for an additional 10 minutes and then, after adjusting the pH to 5.5 using sodium aluminate, sheets are formed. A clear white sheet is obtained, which fluoresces under ultraviolet light or daylight, and shows no yellow tinge.

Similar results are obtained using 0.14 part of the brightener composition of Example 3. When the same experiment is performed using the same quantity of compound A the results are unsatisfactory, shows appreciable yellowing.

Example 6 7 5 at 220 F. for 3 minutes. The resulting sheets are con- Example 1 is followed except that and the paper i Q siderably whiter than control sheets similarly coated but a member selected from the group consisting of (a) a mix- 1 ture of at least two of three isomeric compounds rep- 10 resented by the following formula:

0.66 per diaminostilbene moiety, and (b) a salt of the "diaminostilbene moiety.

6. A process of brightening paper which comprises conwithout addition of a brightener. When the same experiment is performed using compound A the starch blend is yellow and unsuitable for use in a tub-sizing operation.

I'claim: 1. An aqueous brightener composition consisting essentially of water and at least 0.01 weight percent of a I composition of claim 1.

7.- The process of claim 4 wherein the average occur- 5 rence of the meta-sulfophenyl radical is 0.5 per diaminostilbene moiety.

8. The process of claim 4 wherein the average occurrence of the meta-sulfophenyl radical is 0.66per diaminostilbene moiety.

paper and from 0.01% to 0.2%, based on the weight of SH S0311 the paper, of a member selected from the group consisting of (a) a mixture of at least two of three isomeric compounds represented by the following formula:

wherein the R radicals are meta-sulfophenyl and parasulfophenyl, the average occurrence of meta-sulfophenyl 1n the entire composition being between about 0.33 and ITIH IIIH wherein the R radicals are meta-sulfopheny1 and parasulfophenyl, the average'occurrence of meta-sulfophenyl in the entire composition being between about 0.33 and 0.66 per diarninostilbene moiety, and (b) a salt of the compounds recited in (a) wherein the salt-forming cation is a member selected from the group consisting of sodium,

40 potassium and ammonium.

References Cited in the file of this patent UNITED STATES PATENTS compounds recited in (a) wherein the salt-forming cation 35 is a member selected from the group consisting of sodium, potassium and ammonium.

2. The composition of claim 1 wherein the average occurrence of the meta-sulfophenyl radical is 0.66 per 3. The composition of claim 1 wherein the average occurrence of the meta-sulfophenyl radical is 0.5 per diaminosti1bene moiety.

4. A process of brightening paper which comprises con- 2,924,549 Klein et al. Feb. 9, 1960 cting said paper with a composition of claim 1. I 45 2,945,762 Carroll et al. July 19, 1960 C 5. Aprocess of brightening paper which comprises 0011- 3,012,971 Gessner et al. Dec. 12, 1961 tacting paper pulp with the composition of claim 1. 3,025,242 Seyler Mar. 13,, 1962 tacting sheet paper, during a finishing operation, with the I 9. A composition of matter consisting essentially of 

1. AN AQUEOUS BRIGHTENER COMPOSTION CONSISTING ESSENTIALLY OF WATER AND AT LEAST 0.01 WEIGHT PERCENT OF A MEMBER SELECTED FROM THE GROUP CONSISTING OF (A) A MIXTURE OF AT LEAST TWO OF THREE ISOMERIC COMPOUNDS REPRESENTED BY THE FOLLOWING FORMULA: 